Waitrose & Partners’ sales were down 2.1% for the week to August 17 as the country “continued to experience mixed weather”.

Ambient and non-ambient food sales both fell 1.8% despite a 9% increase in home baking products ahead of the first episode of TV show The Great British Bake Off’s new series.

The grocer announced it would be the first supermarket to sell pullet eggs – smaller eggs produced by younger hens at around 18 weeks old – to offer its customers “the best quality eggs you can get for cooking”.